Current Publications
An airfoil-based synthetic actuator disk model for wind turbine aerodynamic and structural analysis
Muhammad Rubayat Bin Shahadat, Mohammad Hossein Doranehgard, Weibing Cai,
Charles Meneveau, Benjamin Schafer, Zheng Li
This study introduces an airfoil-based refinement technique to enhance the Actuator Disk Model (ADM) for improved wind turbine aerodynamic load prediction and structural simulation in conjunction with Large Eddy Simulations of the wind flow. While ADM offers higher computational efficiency than the more detailed but resource-intensive Actuator Line Model (ALM), it traditionally lacks the resolution needed to capture the localized blade forces accurately. To address this limitation, we introduce a refinement technique that uses airfoil-specific data and employs interpolation-based grid point refinement, achieving ALM-comparable accuracy while preserving ADM’s efficiency. Unlike conventional ADM that provides only rotor-disk averaged forces, our synthetic method tracks transient aerodynamic load variations over multiple blade revolutions, allowing us to calculate the distributions of maximum and minimum loads during typical cycles. Applied to the NREL 5 MW reference turbine, our enhanced ADM accurately predicts key aerodynamic parameters (angle of attack, axial velocity, lift, drag, axial and tangential forces along the blades) as well as structural responses (blade tip deflection, maximum stress, and stress concentration). Our results show that the tip deflection ranges from 2.33m (3.69 % of blade length) to 4.28m (6.79 %), with maximum stress concentration occurring near the blade root. This research demonstrates that a refined synthetic ADM approach can serve as a computationally efficient alternative for both aerodynamic analysis and structural simulation of wind turbine blades subjected to realistic wind fields.
Large eddy simulation of wind farm performance in horizontally and vertically staggered layouts
Muhammad Rubayat Bin Shahadat, Mohammad Hossein Doranehgard, Weibing Cai, Zheng Li
This numerical investigation employs Large Eddy Simulation (LES) coupled with Actuator Disk Model (ADM) to evaluate wind farm layout optimization strategies. The study presents a systematic analysis of aligned, horizontal staggering, vertical staggering, and mixed (combination of horizontal and vertical) staggering configurations, aiming to establish optimal design parameters for enhanced power production. The investigation examines key performance metrics including mean velocity distributions, turbulence intensity characteristics, and power generation efficiency. Results demonstrate better performance of both horizontal and vertical staggering patterns compared to conventional aligned configurations, with horizontal staggering exhibiting notably higher power output than vertical arrangements. Our findings also suggest that mixed configurations, incorporating both horizontal and vertical staggering, can offer optimal performance characteristics. This research advances the understanding of wake interactions in complex wind farm layouts and provides design guidelines for maximizing wind farm power generation efficiency through strategic turbine positioning.
Comparative analysis of drug deposition patterns among three commercial nasal spray brands: A computational and experimental study
Guiliang Liu, Mohammad Hossein Doranehgard, Xuan Ruan, Bingkai Chen, Brent Senior, Adam Kimple, Rui Ni, Zheng Li
This study investigates drug deposition patterns in nasal drug delivery by combining experimental measurements with computational fluid dynamics simulations. We analyzed three, over the counter, mometasone nasal spray devices, experimentally characterizing particle diameter (dp), spray velocity (up), and spray angle (α). Unlike previous studies that relied on assumed parameters or single-brand analyses, we conducted comparative analyses using measured parameters integrated into COMSOL Multiphysics simulations. The study optimized the Line of Sight (LOS) method by exploring various spray positions and instructions to avoid anterior loss of medication in the anterior nasal cavity. Results revealed that Brand 3, with its narrow spray angle, achieved superior drug delivery efficiency when properly aligned with the target region. However, its performance decreased significantly when misaligned due to its smaller spray cone angle. Our findings show that sprays with narrower cone angles delivered medicine more effectively to the ostiomeatal complex (OMC) with up to 44% higher efficiency using the LOS method. Additionally, in cases with septal deviation, we observed a 14–20% higher drug deposition rate in the right nasal cavity compared to the left. The LOS method significantly improved drug deposition by 2.86–3 times, while the Deep Spray method further enhanced it by 38–50%. This integrated experimental-computational approach provides practical insights for optimizing nasal spray device design and administration techniques, particularly considering anatomical variations.
Computational Modeling of Nasal Cavity Aerodynamics: Implications for Surgical Outcomes and Targeted Drug Administration
Guiliang Liu, W. Jared Martin, Yasine Mirmozaffari, Rui Ni, and Zheng Li
The primary goal of sinonasal surgery is to improve a patient’s quality of life, which is generally achieved by enhancing drug delivery (eg, saline rinses, nasal steroids) and nasal airflow. Both drug delivery and nasal airflow are dependent on the anatomic structure of the sinonasal cavity and the relationship between this anatomy and airflow and drug delivery can be studied using computational fluid dynamics (CFD). CFD generally uses computed tomography scans and computational algorithms to predict airflow or drug delivery and can help us understand surgical outcomes and optimize drug delivery for patients. This study employs CFD to simulate nasal airflow dynamics and optimize drug delivery in the nasal cavity to highlight the utility of CFD for studying sinonasal disease. Utilizing COMSOL Multiphysics software, we developed detailed models to analyze changes in airflow characteristics before and after functional endoscopic sinus surgery, focusing on pressure distribution, velocity profiles, streamline patterns, and heat transfer. This research examines the impact of varying levels of nasal airway obstruction on airflow and heat transfer. In addition, we explore the characteristics of nasal drug delivery by simulating diverse spray parameters, including particle size, spray angle, and velocity. Our comprehensive approach allows for the visualization of drug particle trajectories and deposition patterns, providing crucial insights for enhancing surgical outcomes and improving targeted drug administration. By integrating patient-specific nasal cavity models and considering factors such as airway outlet pressure, this study offers valuable data on pressure cross-sections, flow rate variations, and particle behavior within the nasal passages. The findings of this research can be useful for both surgical planning and the development of more effective nasal drug delivery methods, potentially leading to enhanced clinical outcomes in respiratory treatment.